Thomas Hobbes was still a tutor to young William Cavendish, the 3rd Earl of Devonshire during the 1630s. Hobbes first heard of Grantville from his friend and colleague Doctor William Harvey, who had traveled to the town. Hobbes shared what Harvey had told him with Lady Christian Cavendish, who then tasked Hobbes to travel to the American town to determine the future of the Cavendish family. To conceal Hobbes' assignment, he was to take William Cavendish on a Grand Tour of the European continent before finally arriving at Grantville.
On their tour of Europe, Hobbes and William met Marin Mersenne, a friend of William's uncle, in France. Mersenne gave them a letter of introduction to Galileo Galilei, who they met in December of 1632, when they had reached Italy. After many mishaps, the two finally arrived at Grantville in July, 1633.
Hobbes was able to read about the history of the Cavendishes and himself. He was amused to learn that he later became a political philosopher, and was deeply satisfied that he was remembered as one of the greatest English political thinkers. However, he was unhappy to learn that in the aftermath of the English Civil War, he managed to antagonize both sides of the fight. Hobbes was even more unhappy to learn that in later years, suspicions arose that he was an atheist, and that his attack upon ecclesiastical authority enraged both Anglicans and French Catholics, and that copies of his books were publicly burned at Oxford in 1687.
Hobbes also learned that, in the OTL, William had had a son who had been a leader of the Glorious Revolution of 1688-89, which had unseated James II, the last Stuart king of England. He wondered if Charles I knew about that, and if it would cause problems for the Cavendish family.
While staying in Grantville, William Cavendish became friends with the predominantly female Barbie Consortium. He became infatuated with member Judith Wendell, to Hobbes' dismay. Hobbes was certain that Lady Cavendish would blame him for her son's "foreign romantic entanglements". However, when Hobbes learned that Judith's father, Fletcher Wendell, was the Secretary of the Treasury, and thus, similar to a nobleman, he concluded that Judith was a suitable match for William.
In September, Hobbes learned of the League of Ostend's war against the Confederated Principalities of Europe. As England was a member of the League, he and William became persona non grata in the CPoE, or at least in Grantville. But Hobbes also learned that, because he and William had stayed in an enemy territory, the Privy Council could begin making subtle accusations of treason against the two men. Morosely, Hobbes and William went to Hamburg to catch a ship back to England. At the last minute, Hobbes decided to stay in Grantville, partly to continue his research on the Cavendish family history, and to be able to send word of any critical new developments back home, but also because he was sure that only the Americans would tolerate his views on religion. In keeping contact with the Cavendishes, Hobbes told William to send letters to his tutor discreetly. In the weeks that followed, Hobbes received an unsigned letter from his student, addressed to him with the drawn form of the tiger Hobbes from Calvin and Hobbes, which William had tried to show him.